This invention relates to piperidinoquinazolines which are phosphodiesterase inhibitors and cardiac stimulants of which a preferred class selectively increase the force of myocardial contraction without producing significant increases in heart rate. The compounds are useful in the curative or prophylactic treatment of cardiac conditions, in particular heart failure.
Quinazolines are a well-known class of organic compounds, some of which are reported to have useful therapeutic properties. U.S. Pat. No. 3,517,005 discloses 4-aminoquinazoline derivatives with hypotensive and bronchodilator activity, and U.S. Pat. No. 3,511,836 reports hypotensive activity for 2,4-diaminoquinazolines. Scarborough et al., J. Org. Chem., 27, 957 (1967) reports the preparation of several 4-(1-substituted-3-pyrrolidinylmethylamino)quinazolines. U.S. Pat. No. 3,971,783 discloses various 4-(heteroarylalkylamino)quinazolines as cardiac stimulants. U.S. Pat. Nos. 4,001,422 and 4,188,391 disclose various cardiac stimulating 4-(heteroaryl)quinazolines, including certain 4-[4-(alkanesulfonamido)piperidino]quinazolines and 4-[4-(alkanesulfonamidoalkyl)piperidino]quinazolines.